NGF antagonists for medical use

A polypeptide comprising at least one extracellular domain of a TrkA polypeptide (TrkA ECD polypeptide) from a companion animal species and a fusion partner;

• wherein the TrkA ECD polypeptide comprises SEQ ID NO:
• 2, SEQ ID NO:
• 3, SEQ ID NO:
• 4, or SEQ ID NO:
• 5, except that the TrkA ECD polypeptide comprises a pair of cysteine substitutions selected from the group consisting of:
• a) a cysteine at a position corresponding to position 7 and position 89 of SEQ ID NO:
• 2, SEQ ID NO:
• 3, or SEQ ID NO:
• 4;
• or
• b) a cysteine at a position corresponding to position 5 and position 87 of SEQ ID NO:
• 5;
• or
• c) a cysteine at position 7 and position 89 of SEQ ID NO:
• 2, SEQ ID NO:
• 3, or SEQ ID NO:
• 4;
• or
• d) a cysteine at position 5 and position 87 of SEQ ID NO:
• 5.